ASTM E2168-2006 Standard Classification for Allowance Contingency and Reserve Sums in Building Construction Estimating《建筑结构估算中容许偏差、偶然事故和储备量的标准分类》.pdf

《ASTM E2168-2006 Standard Classification for Allowance Contingency and Reserve Sums in Building Construction Estimating《建筑结构估算中容许偏差、偶然事故和储备量的标准分类》.pdf》由会员分享，可在线阅读，更多相关《ASTM E2168-2006 Standard Classification for Allowance Contingency and Reserve Sums in Building Construction Estimating《建筑结构估算中容许偏差、偶然事故和储备量的标准分类》.pdf（4页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: E 2168 06Standard Classification forAllowance, Contingency and Reserve Sums in BuildingConstruction Estimating1This standard is issued under the fixed designation E 2168; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,

2、 the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONIn building construction estimating the terms allowance, contingency and reserve are often usedalmost in

3、terchangeably and are assumed to be universally understood, yet they often mean differentthings to different people. Consequently they can be ambiguous in meaning and intent.Applying these terms, as classified herein, adds a needed precision and rigor in their use as eachterm is held to be specific

4、in its meaning, intent, and use.1. Scope1.1 This classification establishes a classification for allow-ance, contingency, and reserve sums used in construction,project, and program estimating.1.2 This classification applies to all construction work.1.3 This classification is not based on permanent p

5、hysicalelements of construction (as defined and classified in Classifi-cation E 1557. Rather, the classification items are cost compo-nents common to construction, project, and program estimates.2. Referenced Documents2.1 ASTM Standards:2E 631 Terminology of Building ConstructionsE 883 Guide for Ref

6、lectedLight PhotomicrographyE 1557 Classification for Building Elements and RelatedSiteworkUNIFORMAT IIE 1804 Practice for Performing and Reporting Cost Analy-sis During the Design Phase of a ProjectE 1946 Practice for Measuring Cost Risk of Buildings andBuilding Systems3. Terminology3.1 Definitions

7、For definitions of terms used in this clas-sification, refer to Terminologies E 631 and E 833.4. Significance and Use4.1 When preparing construction, project, and program costestimates, it is often necessary to make monetary provision forchange and/or risk or other exigencies where information isinc

8、omplete.4.2 Such allowance, contingency or reserve sums are em-ployed by many persons engaged in the planning, delivery, andfinancing of construction work.4.3 These users include owners, developers, facilities pro-grammers, cost planners, estimators, schedules, architects andengineers, specification

9、 writers, operating and maintenancestaff, manufacturers, educators, financial managers, and comp-trollers.4.4 Usage:4.4.1 These sums are especially appropriate when perform-ing the following activities:Cost budgeting,Conceptual, design and construction cost estimating,Preparing complete forecast cos

10、t for economic evaluation, invest-ment analysis and approval,Controlling cost during planning, design and construction.4.4.2 In any of these activities a needed requirement, orcomponent, of the planned construction can be known whilethe defined solution, design or specification, for providing thisma

11、y not. The usual, and appropriate, response in these situa-tions, is the inclusion of a monetary sum, within an estimate, toprovide for this (these) requirement(s).4.4.3 Such sums may be general or specific in scope, may beplanned to be spent or may only be included as possiblemitigation for unplann

12、ed events and requirements.4.4.4 To distinguish between these sums, and in recognitionof their differing purpose, they are described, and classifiedhere, using the terms allowance, contingency or reserve.1This classification is under the jurisdiction of ASTM Committee E06 onPerformance of Buildings

13、and is the direct responsibility of Subcommittee E06.81on Building Economics.Current edition approved Sept. 1, 2006. Published September 2006. Originallyapproved in 2001. Last previous edition approved in 2001 as E 2168 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orconta

14、ct ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.NOTE 1Section 5 include

15、s a generic statement of purpose for each ofthe three terms and provides a sub-classification that distinguishesbetween sums included for specific purposes and for non-specific i.e.general purposes. In cost budgeting, conceptual and design estimatingespecially, an estimator may intuitively recognize

16、 the need for a generalpurpose sum. This recognition comes in the absence of any known specificrequirement other than the need to ensure the estimate total is a reasonedforecast of a reasonable bid result.4.5 This classification defines allowance, contingency andreserve sums as items common to const

17、ruction, project, andprogram estimates through planning, design, construction, andcompletion. The terms are sufficiently generic to be applied inall forms of construction work.5. Basis of Classification5.1 Classification Criteria:5.1.1 The selected classification of terms is based on thefollowing cr

18、iteria. The terms shall:be readily distinguishable one from the other;be simple and must identify their properties and usage directly;be appropriate in all forms of construction financial activities, and;allow a distinction between the environments (internal or externalwithin which they are applied.

19、5.2 Primary Classification:5.2.1 AllowanceA sum of money that is intended to bespent on the planned scope of work. Used in the absence ofprecise knowledge, and estimated, to the best of ones abilities,to ensure a full and complete estimate. Allowances coverevents and activities that are normally int

20、ernal and so aredirectly controllable within the project plan.5.2.2 ContingencyA sum of money that is provided tocover the occurrence of unintended departures from theplanned scope of work. Used in the absence of preciseknowledge, and estimated, to the best of ones knowledge toensure that a financia

21、l buffer is available within a budget.Contingencies assist in mitigating the effects of unplannedevents and other risks that are external to, and are not directlycontrollable within, a project plan.5.2.3 ReserveAsum, usually held by management (client)to be disbursed only when project requirements a

22、re changed.Used to provide insurance against a project or program failingto complete on budget or for the revision of a budget in the caseof changed management or program direction and requirement.NOTE 2For the purposes of the classification an internal environmentis that which exists within an orga

23、nization. An internal environment mayreadily allow cost control through revision of design or specification, orboth. External environment changes impact the project cost and may bethe result of contractual obligation, uncovered site conditions or changedlegislation, for example. External environment

24、 changes may allow little orno opportunity for mitigation.5.3 Secondary Classification:5.3.1 Each of the Primary Classifications may be furthersub-classified as:5.3.2 SpecificWhere the content of a sum is uniquelyidentified and the sum is calculated solely for that distinctpurpose, and;5.3.3 Non-Spe

25、cificWhere the content of a sum is onlybroadly identified and the sum is calculated for application tothat general purpose.NOTE 3Reference should also be made to Practice E 1946, whichdescribes a formal methodology for estimating the amount of each sum.NOTE 4For examples of specific allowance items

26、refer to PracticeE 1804.5.4 Classifications in Context:5.4.1 Placing these classifications in the context of typical/generic usage provides an additional understanding of thedistinctions between the classified terms.5.4.2 Table 1 is a tabulation of the basic properties, eventsand methods defined for

27、 allowances, contingencies and re-serves as typically applied in the building construction indus-try. This table identifies the key differences, and some simi-larities, makes for easy identification of the generic principlesdriving the classifications, and so allows consistent application.It also dr

28、aws attention to the need for a subsidiary costclassification that is typically part of a generic Work Break-down Structure.5.5 Subsidiary Classification:TABLE 1 Classification of Allowance, Contingency and ReserveTypical ApplicationAllowance Contingency Reserve1. Intend to spend? Yes No No2. Applie

29、d to work actions that are: Intended Unintended At Client Discretion3. Expenditure is effected by:Internal Change Yes No NoExternal Change No Yes NoManagement (Client) Change No No Yes4. Is an integral part of:Construction Estimate Yes No NoProject Estimate Yes Yes NoProgram Estimate Yes Yes Yes5. C

30、ommitment Sanctioned by:Consultants Yes No NoProject Manager Yes Yes NoManagement (Client) Yes Yes Yes6. Calculated on the basis of:Past Personal/Corporate Experience Yes Yes YesStatistical Analysis of Past Projects Yes Yes YesProbabilistic Assessment of Change Yes No NoProbabilistic Assessment of R

31、isk No Yes NoManagement Policy No No YesE21680625.5.1 Construction EstimateAn estimated cost for theconstruction work including all trade costs and the primecontractors Field Requirements and Office Overhead buildingeconomics, classification, construction estimating; cost esti-mating; cost planning;

32、 cost control; UNIFORMAT II,budgetingAPPENDIX(Nonmandatory Information)X1. GUIDANCE NOTESX1.1 These guidance notes are included to aid in under-standing the application of the classification terms. A simpleand relatively common arrangement used in building construc-tion has been used as an example,

33、describing a common usage.X1.2 Most especially with design construction estimatesthere is a need to make provision for the, as yet, undefineddetail. It is necessary to make allowance for this if an estimatetotal is to be a reasoned forecast of construction cost. Anestimate based on complete drawings

34、 and specifications willinclude only those allowances specifically prescribed in thatdocumentation. Both specific allowances and non specificallowances may be required, particularly during the earlydesign stages.X1.3 The example considers just three levels of a typicalWork Breakdown Structureprogram

35、, project, andconstructionand the cost estimates within them. Each rollsup into the other, with program being the top level. In theexample it is assumed that responsibility for maintaining theselevels within budget is delegated down from management/client (program), to project manager (project), to

36、consultant(construction), although each level has an oversight responsi-bility for their subordinates actions. Table 1 uses this hierar-chy.X1.4 Construction LevelWhen summarizing estimatesspecific allowances are usually included within the section towhich they apply, that is, an allowance for rock

37、excavationwould be included within the appropriate trade or elementalcategory. Non-specific allowances, by their very nature, cannotbe treated that way and so must be included in a unique sectionor category of their own. In architectural building parlance, anallowance is sometimes described as provi

38、sion for a deferred orevolving design decision.NOTE X1.1This summary methodology and its distinction betweenthe specific and the nonspecific also applies to contingencies and reserves.X1.5 Project LevelA project manager, whose responsi-bility is to deliver a project “on time and within budget,” will

39、make provision within the project estimate for risk items whenadvising management of their financial exposure. This may bedone by including a contingency sum within the total forecastproject cost. Although estimated in several possible wayscontingency sums should reflect both the upside and down sid

40、eof identified project risks. Contingencies are reasoned sumsthat take into account the probability of occurrence of suchidentified risks. Such sums may likely be included for fundsappropriation purposes and are only to be expended, as needed,against those risks.X1.6 Program LevelA prudent client ma

41、y also makeprovision for changes in overall program direction, changes inrequirement or other unavoidable changes. A managementreserve is the usual approach. For purposes of this discussion,a program may include several projects but only one reserve.Such reserves are controlled by the client and the

42、 amount maybe based on company policy, calculation, or the recommenda-tion of others. Again it is a measure of possible exposure andis for use in the event that the client needs to change theprograms direction. Similar in many respects to a contingencythe name reserve identifies the party concerned

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46、known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).E2168064